1. Field of the Invention
The present invention is directed to a fiber optical bypass relay or switch for selectively connecting an incoming line fiber and an outgoing line fiber to a pair of subscriber fibers extending to a subscriber station and bypassing the subscriber station by interconnecting the incoming line fiber to the outgoing line fiber which switch has movement of a single part which is biased against one stop and is then moved to another stop.
In a fiber optical communication system with a ring network structure, a plurality of subscriber stations are connected in series with the line fiber for receiving the communication signal. If a repeater has been turned off at the subscriber station or if the repeater is malfunctioning, it is desirable that this particular station be bypassed and thus a fiber optical bypass switch or bridge is provided in the ring network or structure for each station to enable bypassing each station.
A fiber optical bypass relay or switch for bypassing a repeater or station in a fiber optical communication system is disclosed by E.G. Rawson et al, "A Fiber Optical Relay for Bypassing Computer Network Repeaters", Optical Engineering, Vol. 19, No. 4, July/August 1980, pages 628-9. This fiber optical bypass relay is an opto-mechanical relay which exhibits only one movable part. The incoming line fiber from the fiber optical path and the subscriber fiber incoming from the repeater or station to the optical bypass relay are fixed to this movable part which consists of a ferro-magnetic material. The outgoing line fiber which extends to the fiber optical path and a subscriber fiber which leads to the repeater or subscriber station are secured on a stationary plate or lamina. The movable part is moved back and forth between two positions or stops by means of a magnetic coil and an additional spring arrangement. When the moving part rests at one of the two stops, the repeater or subscriber station is bypassed because the incoming line fiber is connected to the outgoing line fiber. When the moving part is moved against the other stop, then the repeater is incorporated in the fiber optical communication path because the incoming line fiber is connected to the subscriber fiber leading to the subscriber station and the outgoing line fiber is connected to the subscriber fiber extending from the subscriber station. A disadvantage of this known fiber optical bypass relay is the motion of the moving part between the two positions does not occur in a contact-free manner, but on the contrary, the moving part slides over a substrate during this motion. This sliding of the moving part across the substrate causes wear between the moving part and the substrate which limits the useful life of the fiber optical bypass relay and the sliding also increases the required power for operating the switch or the making and breaking capacity of the switch.